The present invention relates to fluid flow rate measurement devices, and more particularly to fluid flow rate measurement devices for water pipes in chiller systems.
Fluid flow rate measurement devices typically include a measuring probe that measures fluid flow in a water pipe. The fluid flow rate measurement device is used to measure actual fluid flow in the water pipe.
In chiller systems, a sufficient amount of water flow through the evaporator is important to inhibit the water from freezing in the evaporator. Extraneous factors such as pump malfunction, clogs in the water lines, or partial freezing of the water in the water lines can decrease the water flow rate to a rate insufficient to prevent freezing of the water in the evaporator. To ensure that the chiller does not continue to operate when water flow is insufficient to prevent freezing, the chiller system monitors the water flow rate using the input from the measuring probe and compares the measured flow rate to a water flow trip point. When the measured flow rate is at or below the water flow trip point, the chiller system is shut off in order to prevent water from freezing. A service technician is required to address the low water flow issue prior to restarting the chiller system.
In some cases, due to turbulence or a water flow sensor with high variability, an inaccurate water flow measurement resulting in a water flow measurement above the intended water flow trip point may cause the chiller system to be shut off unnecessarily. This is referred to as a “nuisance trip”.